Question

How many of the following letters have at least one line of symmetry?

A.$2$
B.$4$
C.$5$
D.$6$

Answer 1

Hint: The line of symmetry is the line which divides the image into two mirror images. It can be vertical, horizontal or diagonal. The image can also have more than one line of symmetry.

Complete step-by-step answer:
The line of symmetry is an imaginary line or axis along which the figure when folded gives symmetrical or identical halves. These halves are mirror images of each other.
We have to find the number of letters that have at least one line of symmetry.

The letter O is in the shape of a circle. In a circle any line that passes through the center of the circle is a line of symmetry. So a circle has an infinite number of lines of symmetry.
Letter L and P have no line of symmetry because the line does not divide the letter into two mirror images whether it is vertical, diagonal or horizontal.
Letter Y, M, I and A have one line of symmetry which is vertical.
Letter D has one horizontal line of symmetry.
Hence the correct answer is D.

Note: In line of symmetry, following points are important-
The folded sides of the figure must coincide if it is folded along the line of symmetry.
It is not necessary that all lines that divide a figure into two congruent halves or mirror images are lines of symmetry. For example- The diagonal of a rectangle divides it into two congruent triangles but when we fold the figure along the diagonal the lines of one side do not coincide with the other side. Hence the diagonal; of a triangle is not a line of symmetry.
The lines of symmetry of regular polygons are equal to the number of the sides.
It is also called reflection symmetry.